From ba9c4f88d747836bf35c3eee36aa18d2e164f493 Mon Sep 17 00:00:00 2001 From: "Steven J. Magnani" Date: Thu, 13 May 2010 10:48:27 -0500 Subject: [PATCH] microblaze: Allow PAGE_SIZE configuration Allow developer to configure memory page size at compile time. Larger pages can improve performance on some workloads. Based on PowerPC code. Signed-off-by: Steven J. Magnani Signed-off-by: Michal Simek --- arch/microblaze/Kconfig | 30 ++++++++++++++++++++++++++++ arch/microblaze/include/asm/elf.h | 2 +- arch/microblaze/include/asm/page.h | 12 +++++++++-- arch/microblaze/kernel/cpu/mb.c | 1 + arch/microblaze/kernel/head.S | 4 ++-- arch/microblaze/kernel/vmlinux.lds.S | 12 +++++------ 6 files changed, 50 insertions(+), 11 deletions(-) diff --git a/arch/microblaze/Kconfig b/arch/microblaze/Kconfig index 505a08592423..a51742190c12 100644 --- a/arch/microblaze/Kconfig +++ b/arch/microblaze/Kconfig @@ -223,6 +223,36 @@ config TASK_SIZE hex "Size of user task space" if TASK_SIZE_BOOL default "0x80000000" +choice + prompt "Page size" + default MICROBLAZE_4K_PAGES + depends on ADVANCED_OPTIONS && !MMU + help + Select the kernel logical page size. Increasing the page size + will reduce software overhead at each page boundary, allow + hardware prefetch mechanisms to be more effective, and allow + larger dma transfers increasing IO efficiency and reducing + overhead. However the utilization of memory will increase. + For example, each cached file will using a multiple of the + page size to hold its contents and the difference between the + end of file and the end of page is wasted. + + If unsure, choose 4K_PAGES. + +config MICROBLAZE_4K_PAGES + bool "4k page size" + +config MICROBLAZE_8K_PAGES + bool "8k page size" + +config MICROBLAZE_16K_PAGES + bool "16k page size" + +config MICROBLAZE_32K_PAGES + bool "32k page size" + +endchoice + endmenu source "mm/Kconfig" diff --git a/arch/microblaze/include/asm/elf.h b/arch/microblaze/include/asm/elf.h index 7d4acf2b278e..732caf1be741 100644 --- a/arch/microblaze/include/asm/elf.h +++ b/arch/microblaze/include/asm/elf.h @@ -77,7 +77,7 @@ typedef elf_fpreg_t elf_fpregset_t[ELF_NFPREG]; #define ELF_DATA ELFDATA2MSB #endif -#define ELF_EXEC_PAGESIZE 4096 +#define ELF_EXEC_PAGESIZE PAGE_SIZE #define ELF_CORE_COPY_REGS(_dest, _regs) \ diff --git a/arch/microblaze/include/asm/page.h b/arch/microblaze/include/asm/page.h index 464ff32bee3d..c12c6dfafd9f 100644 --- a/arch/microblaze/include/asm/page.h +++ b/arch/microblaze/include/asm/page.h @@ -23,8 +23,16 @@ #ifdef __KERNEL__ /* PAGE_SHIFT determines the page size */ -#define PAGE_SHIFT (12) -#define PAGE_SIZE (_AC(1, UL) << PAGE_SHIFT) +#if defined(CONFIG_MICROBLAZE_32K_PAGES) +#define PAGE_SHIFT 15 +#elif defined(CONFIG_MICROBLAZE_16K_PAGES) +#define PAGE_SHIFT 14 +#elif defined(CONFIG_MICROBLAZE_8K_PAGES) +#define PAGE_SHIFT 13 +#else +#define PAGE_SHIFT 12 +#endif +#define PAGE_SIZE (ASM_CONST(1) << PAGE_SHIFT) #define PAGE_MASK (~(PAGE_SIZE-1)) #define LOAD_OFFSET ASM_CONST((CONFIG_KERNEL_START-CONFIG_KERNEL_BASE_ADDR)) diff --git a/arch/microblaze/kernel/cpu/mb.c b/arch/microblaze/kernel/cpu/mb.c index 4216eb1eaa32..7086e3564281 100644 --- a/arch/microblaze/kernel/cpu/mb.c +++ b/arch/microblaze/kernel/cpu/mb.c @@ -126,6 +126,7 @@ static int show_cpuinfo(struct seq_file *m, void *v) cpuinfo.pvr_user1, cpuinfo.pvr_user2); + count += seq_printf(m, "Page size:\t%lu\n", PAGE_SIZE); return 0; } diff --git a/arch/microblaze/kernel/head.S b/arch/microblaze/kernel/head.S index 1bf739888260..42434008209e 100644 --- a/arch/microblaze/kernel/head.S +++ b/arch/microblaze/kernel/head.S @@ -43,10 +43,10 @@ .global empty_zero_page .align 12 empty_zero_page: - .space 4096 + .space PAGE_SIZE .global swapper_pg_dir swapper_pg_dir: - .space 4096 + .space PAGE_SIZE #endif /* CONFIG_MMU */ diff --git a/arch/microblaze/kernel/vmlinux.lds.S b/arch/microblaze/kernel/vmlinux.lds.S index db72d7124602..b0de1a6b5513 100644 --- a/arch/microblaze/kernel/vmlinux.lds.S +++ b/arch/microblaze/kernel/vmlinux.lds.S @@ -55,7 +55,7 @@ SECTIONS { */ .sdata2 : AT(ADDR(.sdata2) - LOAD_OFFSET) { _ssrw = .; - . = ALIGN(4096); /* page aligned when MMU used - origin 0x8 */ + . = ALIGN(PAGE_SIZE); /* page aligned when MMU used */ *(.sdata2) . = ALIGN(8); _essrw = .; @@ -70,7 +70,7 @@ SECTIONS { /* Reserve some low RAM for r0 based memory references */ . = ALIGN(0x4) ; r0_ram = . ; - . = . + 4096; /* a page should be enough */ + . = . + PAGE_SIZE; /* a page should be enough */ /* Under the microblaze ABI, .sdata and .sbss must be contiguous */ . = ALIGN(8); @@ -120,7 +120,7 @@ SECTIONS { __init_end_before_initramfs = .; - .init.ramfs ALIGN(4096) : AT(ADDR(.init.ramfs) - LOAD_OFFSET) { + .init.ramfs ALIGN(PAGE_SIZE) : AT(ADDR(.init.ramfs) - LOAD_OFFSET) { __initramfs_start = .; *(.init.ramfs) __initramfs_end = .; @@ -132,11 +132,11 @@ SECTIONS { * so that __init_end == __bss_start. This will make image.elf * consistent with the image.bin */ - /* . = ALIGN(4096); */ + /* . = ALIGN(PAGE_SIZE); */ } __init_end = .; - .bss ALIGN (4096) : AT(ADDR(.bss) - LOAD_OFFSET) { + .bss ALIGN (PAGE_SIZE) : AT(ADDR(.bss) - LOAD_OFFSET) { /* page aligned when MMU used */ __bss_start = . ; *(.bss*) @@ -145,7 +145,7 @@ SECTIONS { __bss_stop = . ; _ebss = . ; } - . = ALIGN(4096); + . = ALIGN(PAGE_SIZE); _end = .; DISCARDS